Some new research was recently published in the American Journal of Clinical Nutrition that contradicts everything we've been following when it comes to fat intake, particularly saturated fat.
For some time it's been believed that a diet reduced in saturated fat was beneficial to heart health. This latest study conducted as a meta-analysis found no significant evidence linking dietary saturated fat with increased risk of heart disease.
If you do not know what a meta-analysis is let me explain. A meta-analysis combines the results of several studies researching related theories. In this case 21 different studies were identified in relation to dietary saturated fat and heart disease risk (coronary artery disease, stroke, and cardiovascular disease). The 21 studies included 347,747 healthy adult participants. Researchers looked at the results of the 21 studies to determine the overall results.
Now, I do like meta-analysis results. They provide a look at the big picture of all the different studies on one particular area to determine the overall findings. However, it is worth noting that there are some weaknesses linked to a meta-analysis.
Here are three known weaknesses:
1. There's a heavy reliance on published studies when completing a meta-analysis. It's difficult to publish studies that do not show significant results or relationships, which may skew meta-analysis results. Let me say this another way, if a meta-analysis only includes studies showing a positive or negative association there could be many unpublished studies that shown no link at all.
2. What studies are included in the meta-analysis are not controlled. This means a meta-analysis may include poorly designed studies that again skew results inaccurately.
3. The last weakness I want to touch on is called the Simpson's Paradox. This weakness has to do with statistics and the interpretation of study results. You may have two small studies providing one result while a combination study provides an opposing result. The decision to include or exclude a study is subjective. There are different ways to measure effect, which is of significant importance when it comes to medicine, and there is no one agreed upon measurement method.
So, why am I sharing this with you? While the results of this latest meta-analysis are interesting I do not recommend you throw out your olive oil and replace it with lard. Granted, saturated fat may not deserve the negative reputation it's received, but that doesn't mean you need excess amounts in your diet. It always comes back to everything in moderation. I encourage you to wait for more studies on the connection between saturated fat and heart disease before making any drastic diet changes.
I'd love to hear your thoughts. Feel free to share them below.